152 research outputs found
Bridging the user equilibrium and the system optimum in static traffic assignment: a review
Solving the road congestion problem is one of the most pressing issues in modern cities since it causes time wasting, pollution, higher industrial costs and huge road maintenance costs. Advances in ITS technologies and the advent of autonomous vehicles are changing mobility dramatically. They enable the implementation of a coordination mechanism, called coordinated traffic assignment, among the sat-nav devices aiming at assigning paths to drivers to eliminate congestion and to reduce the total travel time in traffic networks. Among possible congestion avoidance methods, coordinated traffic assignment is a valuable choice since it does not involve huge investments to expand the road network. Traffic assignments are traditionally devoted to two main perspectives on which the well-known Wardropian principles are inspired: the user equilibrium and the system optimum. User equilibrium is a user-driven traffic assignment in which each user chooses the most convenient path selfishly. It guarantees that fairness among users is respected since, when the equilibrium is reached, all users sharing the same origin and destination will experience the same travel time. The main drawback in a user equilibrium is that the system total travel time is not minimized and, hence, the so-called Price of Anarchy is paid. On the other hand, the system optimum is an efficient system-wide traffic assignment in which drivers are routed on the network in such a way the total travel time is minimized, but users might experience travel times that are higher than the other users travelling from the same origin to the same destination, affecting the compliance. Thus, drawbacks in implementing one of the two assignments can be overcome by hybridizing the two approaches, aiming at bridging users’ fairness to system-wide efficiency. In the last decades, a significant number of attempts have been done to bridge fairness among users and system efficiency in traffic assignments. The survey reviews the state-of-the-art of these trade-off approaches
Public policy for innovation and internationalisation: are they worth it?
This paper investigates empirically determinants of regional growth. The scant literature that exists indicates that a region’s economic growth depends to a large extent on several features of the regions themselves, which evolve slowly over time. Our results contribute to this set of literature, accounting also for policy variables, which have been by far neglected. Indeed, due to numerous market failures, measures to promote innovation and internationalization have been prominent in government policies in the last decade. This follows because, there is a consensus among academics, policy makers and practitioners that innovation and internationalization has become increasingly important for the growth of regions and countries. The effect of such ad hoc policy measures by home governments to promote innovation and internationalization has scarcely been studied, and existing studies addressing this issue have mainly a national focus. Despite the clear theoretical justification for the public support, policy makers ask for robust empirical evidence on these matters. This paper contributes to this end. The novelty of the study is in the emphasis on the impact of public policy tools (for innovation and internationalization), and on the coordination between them, upon regional growth. The study is conducted for the 20 Italian regions over the period 1998 to 2008. It tests not only the importance of regional characteristics but also the effects of public policy measures upon the regional economic growth. We focus in specific in the role of innovation and internationalization policy related measures. The results reveal the importance of regional characteristics and also of policy measures. The empirical findings are in line with the theoretical hypotheses: public incentives are key for promoting growth, and they have to be seen in the broader context of the determinants of regional growth. The paper also derives conclusions regarding the interrelationship between policies for innovation and for internationalization. Moreover, the allocation of incentives does not seem to help counterbalance the regional asymmetry, and the global processes and challenges are likely to strengthen the gap between regions.
How to Organize an OR Workshop: the AIROYoung Experience
AbstractAIROYoung is the Young Researchers Chapter of AIRO (Italian Association of Operations Research). In this work, we focus on the AIROYoung Workshop, an annual event which has been reuniting young researchers constituting this community from 2017. Describing all the editions of the initiative, we highlight the main guidelines we have been following so far to organize it (e.g., no registration fee, grants for free accommodation, no parallel sessions, and a look to sustainability). We analyze surveys filled by participants to present qualitative and quantitative data about our workshops and to show how interest and attendance have increased through the years. We talk about some innovations we have introduced to improve quality (e.g., the PhD school "from young researchers to young researchers" and the pitch talk session). We then share our personal opinion and, last but not least, we invite young researchers to join in the preparation of the next AIROYoung Workshops
A Strong Merger Shock in Abell 665
Deep (103 ks) \chandra\ observations of Abell 665 have revealed rich
structures in this merging galaxy cluster, including a strong shock and two
cold fronts. The newly discovered shock has a Mach number of = 3.0
0.6, propagating in front of a cold disrupted cloud. This makes Abell~665 the
second cluster where a strong merger shock of 3 has been detected,
after the Bullet cluster. The shock velocity from jump conditions is consistent
with (2.7 0.7) 10 km sec. The new data also reveal a
prominent southern cold front, with potentially heated gas ahead of it. Abell
665 also hosts a giant radio halo. There is a hint of diffuse radio emission
extending to the shock at the north, which needs to be examined with better
radio data. This new strong shock provides a great opportunity to study the
re-acceleration model with the X-ray and radio data combined.Comment: Accepted for publication in ApJ
Diatom communities and ecological status classification in the upper Po River basin
One of the main challenges in river management is the setting of nutrient thresholds that support good ecological status, which is the main objective to achieve for the European member states. This is a complex process, which needs an accurate analysis of the data collected so far for the ecological classification of rivers belonging to different typologies. We analysed the data of the multiannual monitoring concerning diatoms and nutrients in the upper Po River (NW Italy) with the aim of exploring the response of diatom community in terms of species composition, ecological guilds and indices. We considered data of 390 samples, of which 2/3 belonging to the “Central macrotype” (i.e. lowland stretches) and 1/3 to “Alpine siliceous”. We performed a Principal Coordinate Analysis to detect community patterns with respect to water chemical classification and macrotypes highlighting species and ecological guilds characteristic of samples along a water quality gradient. We then performed a partial RDA to focus on the role of environmental and spatial factors in shaping the diatom community in each of the two macrotypes. Finally, we investigated the concordance between the Italian normative indices ICMi (for diatoms) and LIMECO (a chemical index of water quality). We found significant differences in the diatom communities of the two macrotypes and in their response to water quality and to spatial factors. Communities resulted as much more uniform in sites with a low water quality, with characteristic species such as Navicula gregaria, Nitzschia palea and Sellaphora nigri. On the other hands, moderately disturbed sites (in terms of trophic level) were characterised by the highest guild diversity. The RDA confirmed the importance of spatial factors in shaping the diatom assemblages, especially in Alpine streams where the physical barriers may condition species dispersion. The comparison between the two normative indices highlights that the correspondence in the classification is achieved in the 57% (Alpine macrotype) and 43% (Central macrotype) of samples. According to our findings, we suggest the revision of the ICMi, both class boundaries and reference value. In addition, we recommend to lower LIMECO threshold for total phosphorus: indeed, several studies have shown significant changes in the diatom community composition starting from very low values (below the current LIMECO threshold, i.e. 50 µgL-1). Moreover, the extension of our study to the whole Po River basin will complete our knowledge of species not yet included in the diatom indices and of the community response to nutrient levels also in other macrotypes
Use of Octreotide in association with talc poudrage for the management of a severe chylothorax: A case report
Chylothorax is an uncommon form of pleural effusion characterized by the presence of chylomicrons, triglycerides and cholesterol in the physical and chemical examination of the pleural fluid. It may have poor prognosis if not properly treated. Currently, conservative measures are the first line of treatment for managing chylothorax. The aim of our study is to show and suggest the use of octreotide in association with talc poudrage as good option to manage post-operative a severe chylothorax
The Colony-Stimulating Factor-1 (CSF-1) Receptor Sustains ERK1/2 Activation and Proliferation in Breast Cancer Cell Lines
Breast cancer is the second leading cause of cancer-related deaths in western countries. Colony-Stimulating Factor-1 (CSF-1) and its receptor (CSF-1R) regulate macrophage and osteoclast production, trophoblast implantation and mammary gland development. The expression of CSF-1R and/or CSF-1 strongly correlates with poor prognosis in several human epithelial tumors, including breast carcinomas. We demonstrate that CSF-1 and CSF-1R are expressed, although at different levels, in 16/17 breast cancer cell lines tested with no differences among molecular subtypes. The role of CSF-1/CSF-1R in the proliferation of breast cancer cells was then studied in MDAMB468 and SKBR3 cells belonging to different subtypes. CSF-1 administration induced ERK1/2 phosphorylation and enhanced cell proliferation in both cell lines. Furthermore, the inhibition of CSF-1/CSF-1R signaling, by CSF-1R siRNA or imatinib treatment, impaired CSF-1 induced ERK1/2 activation and cell proliferation. We also demonstrate that c-Jun, cyclin D1 and c-Myc, known for their involvement in cell proliferation, are downstream CSF-1R in breast cancer cells. The presence of a proliferative CSF-1/CSF-1R autocrine loop involving ERK1/2 was also found. The wide expression of the CSF-1/CSF-1R pair across breast cancer cell subtypes supports CSF-1/CSF-1R targeting in breast cancer therapy
Allele Specific Locked Nucleic Acid Quantitative PCR (ASLNAqPCR): An Accurate and Cost-Effective Assay to Diagnose and Quantify KRAS and BRAF Mutation
The use of tyrosine kinase inhibitors (TKIs) requires the testing for hot spot mutations of the molecular effectors downstream the membrane-bound tyrosine kinases since their wild type status is expected for response to TKI therapy. We report a novel assay that we have called Allele Specific Locked Nucleic Acid quantitative PCR (ASLNAqPCR). The assay uses LNA-modified allele specific primers and LNA-modified beacon probes to increase sensitivity, specificity and to accurately quantify mutations. We designed primers specific for codon 12/13 KRAS mutations and BRAF V600E, and validated the assay with 300 routine samples from a variety of sources, including cytology specimens. All were analyzed by ASLNAqPCR and Sanger sequencing. Discordant cases were pyrosequenced. ASLNAqPCR correctly identified BRAF and KRAS mutations in all discordant cases and all had a mutated/wild type DNA ratio below the analytical sensitivity of the Sanger method. ASLNAqPCR was 100% specific with greater accuracy, positive and negative predictive values compared with Sanger sequencing. The analytical sensitivity of ASLNAqPCR is 0.1%, allowing quantification of mutated DNA in small neoplastic cell clones. ASLNAqPCR can be performed in any laboratory with real-time PCR equipment, is very cost-effective and can easily be adapted to detect hot spot mutations in other oncogenes
Cancer stem cells and macrophages: molecular connections and future perspectives against cancer.
Cancer stem cells (CSCs) have been considered the key drivers of cancer initiation and progression due to their unlimited self-renewal capacity and their ability to induce tumor formation. Macrophages, particularly tumor-associated macrophages (TAMs), establish a tumor microenvironment to protect and induce CSCs development and dissemination. Many studies in the past decade have been performed to understand the molecular mediators of CSCs and TAMs, and several studies have elucidated the complex crosstalk that occurs between these two cell types. The aim of this review
is to define the complex crosstalk between these two cell types and to highlight potential future anti-cancer strategies
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